1. Field of the Invention
The invention described in this specification relates to a vibrating wire gage.
2. Description of the Prior Art
Vibrating wire gages per se are known in the prior art. The basic principle behind their operation is essentially the same i.e., to vibrate a taut wire, measure its frequency of vibration and then note variations from this measured frequency. One example of such a gage is found in the U.S. Pat. No. 2,969,677 to A. V. Lewis.
Many of the prior art devices have been especially constructed to operate in a certain type of environment. This is true of our invention which was particularly, but not exclusively, developed to operate in a coal mine. Because of the potentially dangerous explosive condition caused by the methane laden air common to underground coal mine excavations, the use of electronically activated devices should be minimized. Also another major factor to be considered is the cost of manufacturing a gage when it is to be used with rockbolts found by the millions throughout mines. Not only must the gage be permissible for underground mine use but it must be safe and simple in operation. All of these factors were taken into consideration in developing our improved gage as it is mechanically activated, simple in operation, and low in cost. Safety, is emphasized as the in situ rockbolt requires no application of force to readout the frequency of the wire's vibration thus doing away with the associate danger of rock falls from rockbolt tightening or loosening when testing torque for bolt security.